Role of Endoluminal Sonography in Evaluation of Obstruction of the Ureteropelvic Junction

Abstract

The objective of this study was to evaluate the clinical feasibility of the use of 2D and 3D endoluminal sonography during endourologic procedures on patients with an obstructed ureteropelvic junction (UPJ). In 45 patients with an obstructed UPJ undergoing endoscopic procedures, a 6.2-French catheter-based ultrasound probe (12.5 or 20 MHz) was inserted under endoscopic guidance into the upper urinary tract for acquisition of 2D images for evaluation of UPJ structures and construction of 3D volume images with a computer workstation. The role of 3D in addition to 2D imaging for identification of abnormalities at the UPJ was evaluated. Both 2D and 3D images depicted crossing vessels at the UPJ in 24 of 43 patients (55.8%) and a ureteral septum in 14 of 43 patients (32.6%), and endoscopic incisions were successfully made with sonographic guidance. The anatomic structures of the UPJ associated with abnormalities (e.g., crossing vessels, septum, calculi, tumors, and strictures) were appreciated and evaluated more fully on 3D than on 2D images. The endoluminal sonographic findings helped rule out or modify the interventional procedure (endopyelotomy or balloon ureteroplasty) in the cases of eight of 43 patients (18.6%). Three-dimensional endoluminal sonography clearly displays diagnostic information that complements 2D imaging findings and enhances the assessment of normal and abnormal structures at the UPJ for endourologic surgery.